Oil prices rose more than 4% on Monday as global markets rallied after governments launched bailout schemes to shore up banks.
Britain, Germany, France, Italy and other European governments all announced rescue packages to stave off the financial crisis.
US crude settled up $US3.49 to $US81.19 a barrel, after a flight of investors into safer havens sent prices to the lowest level since 10 September, 2007, on Friday.
London Brent crude rose $US3.37 to settle at $US77.46 barrel.
Investors previously rushed into oil and other commodities until a slowdown in demand knocked crude oil from a record high of $US147.27 set on 11 July.
The drop in crude prices has prompted some members of the Organization of Petroleum Exporting Countries to call for a reduction in production levels when the cartel holds an emergency meeting on 18 November.